Preparation of olefin metal complexes



United States Patent Office 3,439,009 Patented Apr. 15, 1969 3 439,009 PREPARATION OF OEEFIN METAL COMPLEXES Arthur D. Ketley, Silver Spring, Md., assignor to W. R. Grace & Co., New York, N.Y., a corporation of Connecticut No Drawing. Continuation-impart of application Ser. No. 592,326, Nov. 7, 1966. This application Aug. 2, 1968, Ser. No. 749,619

Int. Cl. C07c 3/10; C07f 15/00 U.S. Cl. 260-429 9 Claims ABSTRACT OF THE DISCLOSURE In abstract, this invention is directed to a process for preparing an olefin-palladium (ll) chloride complex having the formula.

by reacting an aliphatic mono-olefin having 2-12 carbon atoms with palladium(II) chloride in the presence of dioxane or an ether having the formula R O-R where R is an aromatic group having 6-12 carbon atoms, the aromatic nucleus being bonded directly to the O of said ether, and R is a member selected from the group consisting of alkyl having about 1-12 carbon atoms, phenyl, naphthyl, alkaryl having about 6l2 carbon atoms, and aralkyl having about 612 carbon atoms, all as recited hereinafter. The compound has utility as a catalyst for the dimerization of olefins.

This is a continuation-in-part of my application Ser. No. 592,326, filed Nov. 7, 1966 which is now abandoned.

FIELD OF THE INVENTION This invention is in the field of olefin complexes of palladium(II) chloride, being directed to a process for preparing such complexes.

Kharasch, I. Am. Chem. Soc., 1938 60, 882 describes a method for preparing olefin-PdCl complexes, and U.S. Patent No. 3,119,861 also describes the preparation of such complexes.

I have previously shown in my earlier application, Ser. No. 517,087, dated Nov. 23, 1965, that olefin complexes which possess the general formula (olefin) M X wherein the olefin is a lower aliphatic olefin having 2-12 carbon atoms, M is a Group VIII metal cation, including palladium(II), and X is a halogen anion, including chlorine, possess utility as catalysts for the dimerization of olefins.

SUMMARY OF THE INVENTION In summary, this invention is directed to a process for preparing an olefin-palladium(II) chloride complex having the formula.

(olefin) Pd Cl wherein olefin is an aliphatic mono-olefin having about 2-12 carbon atoms, comprising; reacting PdCl with an aliphatic mono-olefin having about 2-l2 carbon atoms in the presence of an ether selected from the group consisting of dioxane and ethers having the formula R O-R wherein R is an aromatic group having 6l2 carbon atoms, the aromatic nucleus of said group being bonded directly to the O of said ether, and R is a member selected from the group consisting of alkyl having about 1-12 carbon atoms, phenyl, naphthyl, alkaryl having about 612 carbon atoms, and aralkyl having about 6-12 carbon atoms. (It is not necessary to separate the thus formed olefin-palladium(II) chloride complex from the ether in which it was prepared if the complex is to be used as a catalyst for the dimerization of olefins because the olefin to be dimerized can be added directly to olefinpalladium(lI) complex-ether mixture formed by the process of the instant invention; however, if desired, said complex can be separated and recovered.)

DESCRIPTION OF PREFERRED EMBODIMENTS In preferred embodiments of the invention described in the above summary:

(1) The olefin is a member selected from the group consisting of ethylene and propylene;

(2) The olefin is a member selected from the group consisting of l-butene and Z-butene;

(3) The ether is anisole;

(4) The ether is dioxane;

( 5) The ether is diphenyl ether;

(6) The ether is phenyl ethyl ether; and

(7) The olefin-palladium(II) chloride complex is separated from the ether. (Separation can be accomplished by filtration, centrifugation, or decantation because the ether is a liquid and the olefin-palladium(II) chloride complex is a solid.)

The olefin-palladium(II) chloride complex which was separated in preferred embodiment 7, supra, can be recovered subsequent to being separated.

DESCRIPTION OF THE INVENTION The reaction of the instant invention is preferably conducted at a temperature in the range of from about 0 to 50 C. with temperatures in the range of 20 to 30 C. being generally preferred. The reaction pressures used to prepare the present complexes can vary from as low as about 0.1 to about atmospheres gauge pressure. The pressure used is not particularly critical, and in general it is most convenient to use only that pressure required to maintain a substantial concentration of the olefin in the reaction medium during the reaction.

The ratio of palladium(II) chloride to the olefin is not particularly critical, however, due to the expense of the metal salt, it is generally preferred to have at least a stoichiometric amount of olefin and preferably an excess. In general, mole ratio of metal salt to olefin in a reaction mixture can vary from about 1:1 to 1:10,000.

In general, the amount of reaction medium (an ether of the type described in the above summary) used in preparing the present complexes ranges from about 10 to about 1000 moles of reaction medium (an ether of the type described in the summary and the preferred embodiments, supra, and following the example, infra) per mole of heavy metal salt used to prepare the present complexes. Using the ratio of reactants generally described herein and the temperatures set forth above, it is found that substantial yields of the desired complex is obtained from about one minute to 24 hours.

My invention, as reported herein, is truly surprising and unexpected because Kharasch et al. (J. Am. Chem. Soc., 1938, 60, 882) report that an ether did not promote the reaction between an olefin and PdCl to form an olefinpalladium(II) chloride complex, and I have found that the reaction fails to occur to a detectable extent where using such ethers as diethyl ether, dimethyl ether, ethyl methyl ether, the ethyl propyl ethers, the methyl propyl ethers, and the dipropyl ethers as reaction medium.

The following example is set forth by way of illustration, and it is understood that the instant invention is not to be construed as being limited by said example or by the details therein.

Example A 5 gram portion of PdCl (a brown solid) was dispersed in 100 ml. of pure freshly distilled anisole in a 250 milliliter glass pressure bottle. The gas in the bottle was flushed out with pure ethylene and ethylene was added to maintain an ethylene pressure of about 100 pounds per square inch gauge pressure (p.s.i.g.) within the bottle while stirring the liquid within the bottle with a plastic coated magnetic stirring bar and While maintaining the temperature of the reacting system within the bottle at about 25 C. After about /2 hour substantially all of the brown PdCl had been converted to yellow solid. The pressure was released from the system, and the yellow solid was separated from the anisole by filtration. The separated solid was dried under vacuum in a vacuum oven at about 35 C. until substantially free of anisole. The dried solid was identified by elemental and infrared analysis as di- -chloro-dichlorobis(ethylene)di-palladium 3 4)2 2 4) Other olefins which'are operable in the process of this invention include but are not limited to propylene, lbutene, 2-butene, l-pentene, Z-pentene, the hexenes, the heptcnes, the octenes, the decylenes, the dodecylenes, 3- methyl-l-pentene, 3-methyl-l-ethyl-l-hexene, 3-methyllbutene, S-methyl-l-hexene, 3,4-dimethyl-l-pentene, 3,3- dimethyl-l-butene, 1-pentene-3-methyl-l-hexene, and the like.

'Other ethers which are operable in the process of this invention include but are not limited to dioxane:

@MMQ

OOH;

O -o-cmomcm Such ethers as diethyl ether, methyl ethyl ether, dimethyl ether, methyl propyl ether, ethyl propyl ether, and dipropyl either are not operative in the process of this invention because, where using such ethers as medium the olefin-palladium(II) chloride complex is not formed in detectable amounts.

Ethers excellently adapted for use in the process of this invention are liquids at the temperature at which the reaction of said process is conducted, preferably having freezing points below room temperature (e.g., below 20- 25 C.) and preferably below 10 C. and for optimum results below about 5 to 0 C.

I claim:

1. A process for preparing an olefin-palladium(II) chloride complex having the formula wherein olefin is an aliphatic mono-olefin having about 2-12 carbon atoms, comprising; reacting PdCl with an aliphatic mono-olefin having about 2-12 carbon atoms in the presence of an ether selected from the group consisting of dioxane and ethers having the formula R O-R wherein R is an aromatic group having 6-12 carbon atoms, the aromatic nucleus of said group'being bonded directly to the O of said ether, and R is a member selected from the group consisting of alkyl having about 1-12 carbon atoms, phenyl, naphthyl, alkaryl having about 6-12 carbon atoms, and aralkyl having about 6-12 carbon atoms.

2. The process of claim 1 in which the olefin is a member selected from the group consisting of ethylene and propylene.

3. The process of claim 1 in which the olefin is a member selected from the group consisting of l-butene and 2-butene.

4. The process of claim 1 in which the ether is anisole.

5. The process of claim 1 in which the ether is dioxane.

6. The process of claim 1 in which the ether is diphenyl ether.

7. The process of claim 1 in which the ether is phenyl ethyl ether.

8. The process of claim 1 in which the olefin-palladium(II) chloride complex is separated from the ether.

6 References Cited UNITED STATES PATENTS 3,119,861 1/1964 Blackham 260544 3,356,748 12/1967 Cramer et al 260653.3

OTHER REFERENCES Kharasch et al.: J. Am. Chem. Soc. 60 (1938), p. 882-4.

10 TOBIAS E. LEVOW, Primary Examiner,

A. P. DEMERS, Assistant Examiner.

US. Cl. X.R.

9. The process of claim 8 in which the separated ole- 15 252-429, 431; 260683.15

fin-pal1adium(II) complex is recovered. 

